Many industrial processes require, either by way of self-imposed constraints or government regulations, that the concentration of certain particulate matter (PM) suspended in a particular fluid (e.g., a gas) not exceed a specified PM concentration threshold. Compliance of a process with a specified PM concentration threshold can be ascertained either periodically or continuously by a PM emission monitor which comprises an array of sensors. If the PM of interest is entrained in a fluent stream that is discharged into the environment, government regulations may require that PM concentration be continuously monitored using sensors that are part of a Continuous Emissions Monitoring System (CEMS).
Integration of a PM emission monitor into a particular CEMS at an industrial facility stack may require periodic calibration of the PM emission monitor in order to maintain accurate readings over time. The necessity and frequency of the calibrations may be prescribed by government regulations, by the manufacturer, or by the end user. In some industrial operations it may be difficult to perform such calibrations, which inherently require that the quantity of PM being discharged from the duct or stack be varied over a range of flow rates. Purposely increasing the PM emissions, for instance, in order to calibrate an installed PM monitor, may result in disruptions to operating equipment and negatively affect the production process at the facility. Facilities would prefer to perform calibration without interrupting the industrial operation which is being monitored.